Bordering states
Iowa vs South Dakota
Short answer
- IA
- 3,241,488
- SD
- 924,669
The two states, county by county
Both maps share one density scale, so the same shade means the same number of people per square mile on either side of the border. Darker counties are denser. Select a county to open its page.
Iowa
South Dakota
- < 5
- < 15
- < 24
- < 40
- ≥ 40
Residents, 2024
- 01Iowa3,241,488
- 02South Dakota924,669
Land, square miles
- 01Iowa55,854
- 02South Dakota75,808
People per square mile
- 01Iowa58.0
- 02South Dakota12.2
Median county household income
- 01Iowa$68,654
- 02South Dakota$67,180
Side by side
| Measure | Iowa | South Dakota |
|---|---|---|
| Residents, 2024 | 3,241,488 | 924,669 |
| Rank by population | 32nd | 46th |
| Land, sq mi | 55,854 | 75,808 |
| People per sq mi | 58.0 | 12.2 |
| County-equivalents | 99 | 66 |
| Median county residents | 15,008 | 5,296 |
| Median county income | $68,654 | $67,180 |
| Most populous county | Polk County | Minnehaha County |
| Largest county by land | Kossuth County | Meade County |
| Capital | Des Moines | Pierre |
| Daylight at capital, June 21 | 15 h 12 min | 15 h 32 min |
| Census division | West North Central | West North Central |
Population and density
Iowa has 3,241,488 residents, 3.5 times South Dakota's 924,669. Iowa ranks 32nd and South Dakota 46th of the 50 states and DC. Iowa is the more crowded, with 58.0 people per square mile against 12.2, 4.8 times.
Land area
South Dakota has 75,808 square miles of land, 36% more than Iowa's 55,854. The largest county-equivalent in Iowa is Kossuth County at 973 square miles; in South Dakota it is Meade County at 3,471.
Counties
Iowa is divided into 99 county-equivalents and South Dakota into 66, so an average Iowa county covers 564 square miles against 1,149. The typical county in Iowa has 15,008 residents, against 5,296 in South Dakota. The most populous are Polk County (516,185) and Minnehaha County (208,639).
5 county names appear on both sides of the border: Clay, Jackson, Jones, Marshall, Union. Use the FIPS code, not the name, when joining data across the two states.
Household income
The typical county household income is about the same in both: $68,654 in Iowa and $67,180 in South Dakota. The highest county incomes are Dallas County ($102,189) in Iowa and Lincoln County ($102,130) in South Dakota, from SAIPE 2023.
Capitals and daylight
Des Moines and Pierre are 391 miles apart in a straight line; from Des Moines the initial bearing is 302°, WNW. On June 21, 2026, Des Moines gets 15 h 12 min of daylight and Pierre 15 h 32 min; on December 21 the figures are 9 h 10 min and 8 h 51 min. Month by month tables are on the Des Moines and Pierre daylight pages.
Where they sit
Both are in the Census West North Central division of the Midwest region. By county internal points, Iowa spans 2 UTM zones and South Dakota 2.
Questions people ask
Which is bigger, Iowa or South Dakota?
South Dakota, with 75,808 square miles of land against 55,854, 1.36 times as large.
Which has more people, Iowa or South Dakota?
Iowa has 3,241,488 residents, 3.5 times South Dakota's 924,669.
How far is Des Moines from Pierre?
391 miles in a straight line, heading WNW (302°) from Des Moines.
Do Iowa and South Dakota have counties with the same name?
Yes, 5: Clay, Jackson, Jones, Marshall, Union.
Sources and data as of
Data as of: Census Vintage 2024 population estimates, 2024 Gazetteer land area and internal points, SAIPE 2023 median household income.
- 01Census Vintage 2024 county population estimates
- 02Census 2024 Gazetteer, counties
- 03Census SAIPE 2023 state and county estimates
- 04Census Bureau regions and divisions of the United States (last verified 2026-09-30)
How every number is computed: methodology. Spotted a wrong figure? Report an error.